The effect of radiation therapy after radical prostatectomy in patients with elevated prostate specific antigen levels.

We analyzed the effects of pelvic radiation therapy given to patients who had an elevated prostate specific antigen level after radical prostatectomy. Among men who previously received adjuvant radiation therapy and had appropriately stored serum 15 had elevated prostate specific antigen levels after radical prostatectomy but before radiation therapy. After radiation therapy the prostate specific antigen level decreased by more than 50% in 80% and to female levels in 53% of the patients. We also prospectively treated 29 men who had increasing levels of prostate specific antigen 9 to 95 months after radical prostatectomy but who were otherwise without evidence of disease by the usual criteria. However, 19 of the patients had local disease as evidenced by random needle biopsy of the urethrovesical anastomosis. Complications of radiation therapy were minimal and maximal prostate specific antigen decrease occurred by 6 months after treatment. In 82% of the patients prostate specific antigen levels decreased by more than 50% and in 43% they decreased to female levels. Female levels were achieved after radiation therapy given many years postoperatively even in stage D1 cancer patients but some of the patients subsequently had increasing prostate specific antigen levels. These data suggest that local-regional disease may be the only site of disease persistence after radical prostatectomy in some of the patients who subsequently have distant metastasis. We conclude that radiation therapy after radical prostatectomy can cause elevated prostate specific antigen to decrease to undetectable levels in many patients but the durability and ultimate therapeutic value of this effect are unknown.